What Is Nattokinase?

Cardiovascular disease kills one person every 34 seconds in the United States — and most people don't know their risk until something goes wrong.

Nattokinase, a fibrinolytic enzyme derived from fermented soybeans, has attracted serious scientific interest for its ability to support healthy blood flow, modulate blood pressure, and help the body manage excess fibrin in the bloodstream. This guide covers what nattokinase is, what the clinical research actually shows, how to take it, and what you need to know about safety before starting.

Table of Contents

1. What Is Nattokinase?
2. How Nattokinase Works: The Science of Fibrinolysis
3. Evidence-Based Nattokinase Benefits
4. Nattokinase Dosage and Timing
5. Safety, Side Effects, and Drug Interactions
6. BioAbsorb Nattokinase — Formulation and Delivery
7. Frequently Asked Questions

What Is Nattokinase?

Nattokinase is a serine protease enzyme extracted from natto — a traditional Japanese fermented soybean food produced using Bacillus subtilis natto bacteria. It was first identified in 1987 by Dr. Hiroyuki Sumi at Chicago University Medical School, who discovered that a substance in natto could dissolve blood clots on a fibrin plate faster than any other food enzyme tested. That substance was nattokinase.

Unlike most food-derived compounds that are metabolized before reaching the bloodstream, nattokinase is absorbed in the small intestine in a form that retains meaningful fibrinolytic activity. Research published in Integrative Medicine Insights describes it as possessing potent fibrinolytic, antihypertensive, anti-atherosclerotic, lipid-lowering, antiplatelet, and neuroprotective effects — an unusually broad cardiovascular profile for a single natural compound.

Natto itself has long been associated with longevity in Japanese populations, and higher natto consumption has been linked to reduced cardiovascular mortality in epidemiological research. The active ingredient responsible for most of those benefits appears to be nattokinase. To learn more about the food source itself, see our guide to natto. Because nattokinase supplements are concentrated and standardized, they offer a more reliable and practical approach than relying on dietary natto — which is not widely available in Western markets and has an acquired taste.

How Nattokinase Works: The Science of Fibrinolysis

To understand why nattokinase has attracted serious cardiovascular research, you need to understand fibrinolysis — the body's natural clot-dissolution system. When a clot forms, it is held together by a protein scaffold called fibrin. The body produces an enzyme called plasmin to break fibrin down. But plasmin's activity is tightly regulated by plasminogen activator inhibitor-1 (PAI-1), which suppresses the enzyme that produces plasmin (tissue plasminogen activator, or tPA). When PAI-1 levels are elevated — which happens with age, obesity, and metabolic stress — the body's clot-clearing capacity weakens.

Nattokinase works through two complementary mechanisms. First, it directly cleaves and degrades fibrin. Second, and more significantly, it inactivates PAI-1 by breaking it into low-molecular-weight fragments — which allows tPA to produce more plasmin, amplifying the body's own fibrinolytic system. According to Memorial Sloan Kettering Cancer Center, the fibrinolytic activity of nattokinase is estimated to be four times that of plasmin itself. For a deeper look at these pathways, see our full mechanism breakdown.

A key piece of human evidence: a double-blind, placebo-controlled crossover study published in Scientific Reports found that a single oral dose of 2,000 FU nattokinase produced measurable increases in fibrin breakdown products and anti-thrombotic markers in healthy subjects within 4 hours of ingestion. This confirmed that orally administered nattokinase can survive digestion and reach the bloodstream in active form — addressing one of the most common questions about enzyme supplementation.

Evidence-Based Nattokinase Benefits

The clinical research on nattokinase covers several cardiovascular outcomes. The evidence is strongest for blood pressure reduction, with supporting data for fibrinolytic activity and arterial health. Here is what the research actually shows — without overstating the evidence or ignoring its limitations.

Blood pressure. A 2023 systematic review and meta-analysis published in Reviews in Cardiovascular Medicine pooled data from 6 randomized controlled trials involving 546 participants and found nattokinase significantly reduced systolic blood pressure by 3.45 mmHg and diastolic by 2.32 mmHg versus placebo. An earlier double-blind, placebo-controlled RCT published in Hypertension Research enrolled 86 participants with pre-hypertension or stage 1 hypertension and found systolic pressure reduced by 5.55 mmHg after 8 weeks of 2,000 FU per day. These reductions are modest compared to prescription medications, but are clinically meaningful and comparable to what lifestyle interventions achieve for mild hypertension. For a full review of the blood pressure data, see our dedicated blood pressure article.

Fibrinolytic and antithrombotic activity. Nattokinase's ability to support healthy clot management is its best-documented property. A multicenter, double-blind, placebo-controlled North American trial in 74 subjects with elevated blood pressure found that 100 mg (2,000 FU) per day for 8 weeks significantly reduced diastolic blood pressure and von Willebrand factor — a cardiovascular risk marker associated with clot formation. The mechanisms are well-established in both in vitro and human studies. For context on this in the setting of specific conditions, see the evidence on blood clots.

Atherosclerosis and arterial health. A large-scale retrospective clinical study published in Frontiers in Cardiovascular Medicine followed 1,062 participants over 12 months and found that nattokinase at higher doses produced a 21.7% reduction in carotid artery intima-media thickness and a measurable reduction in plaque size — key markers of arterial health. It is worth noting that this study used doses well above the standard 2,000 FU. The 2,000 FU dose range showed more modest effects on lipids and atherosclerosis markers in this dataset, which is an honest limitation of the standard supplementation dose. For a cardiovascular-focused summary, see nattokinase and heart health.

Nattokinase Dosage and Timing

The standard clinical dose used in the majority of human trials is 100 mg per day, which corresponds to 2,000 fibrinolytic units (FU) of enzyme activity. The European Food Safety Authority has reported that this dose does not cause adverse effects in short-term human studies, making it the most evidence-supported starting point. Potency matters more than milligrams: two products may both say "100 mg" but have very different activity levels, which is why FU (fibrinolytic units) is the correct way to compare nattokinase supplements. Always verify FU on the label.

Timing has a meaningful impact on how well nattokinase works. Because nattokinase is sensitive to low stomach pH, taking it on an empty stomach — 30 to 60 minutes before eating, or at least two hours after a meal — reduces gastric acid exposure and improves the enzyme's chances of reaching the small intestine intact. Research on nattokinase stability confirms it is rapidly inactivated at pH below 3, which is the typical stomach pH after a meal. Taking it with food may redirect the enzyme toward digesting dietary proteins rather than being absorbed into the bloodstream.

Most trials showing significant results ran for 8 weeks, with measurable effects on blood pressure and fibrinolytic markers appearing consistently at that timeframe. This suggests nattokinase is not a fast-acting supplement — consistent daily use over weeks is required for the cardiovascular benefits seen in clinical research. For a full breakdown of dosing protocols, timing strategies, and what the FU measurement actually means, see the complete dosage guide.

Safety, Side Effects, and Drug Interactions

Nattokinase has a favorable short-term safety record. A real-world safety study that followed patients with vascular diseases taking 100 mg (2,000 FU) nattokinase daily for 30 days reported no adverse events across three groups with different vascular conditions. Mild side effects reported in some clinical studies include digestive symptoms (diarrhea, constipation, stomach discomfort), headache, and in one case an abnormal liver function test. Serious adverse events have not been reported at standard doses in published short-term trials.

The most important safety consideration is drug interactions. Nattokinase has additive fibrinolytic activity with anticoagulant and antiplatelet medications. Anyone taking warfarin (Coumadin), heparin, aspirin, clopidogrel, or other blood-thinning drugs must consult their prescribing physician before using nattokinase. The combination can increase bleeding risk in a clinically meaningful way. According to Memorial Sloan Kettering Cancer Center's integrative medicine database, nattokinase may theoretically increase bleeding risk when combined with anticoagulant, antiplatelet, or fibrinolytic drugs.

Additional cautions apply for people with a history of hemorrhagic stroke, active peptic ulcer, coagulation disorders, or those scheduled for surgery. Use during pregnancy or nursing is not recommended due to insufficient safety data. For a full breakdown of contraindications and known interactions, see the side effects guide and the drug interactions article.

BioAbsorb Nattokinase — Formulation and Delivery

Most nattokinase supplements share the same active ingredient, but formulation choices — particularly how the enzyme is protected through digestion — have a meaningful impact on how much reaches the bloodstream in active form. BioAbsorb Nutraceuticals' Nattokinase Enzyme is built around two formulation decisions that matter.

DRcaps delayed-release capsules. Because nattokinase is inactivated by stomach acid at pH below 3, how the enzyme is delivered matters as much as the dose. BioAbsorb uses DRcaps — a delayed-release veggie capsule technology made from HPMC that resists stomach acid and delays disintegration substantially compared to standard gelatin capsules, releasing the enzyme in the small intestine where absorption conditions are far more favorable. Critically, DRcaps are free of the phthalates and plasticizers found in many standard enteric-coated capsules — a meaningful difference for health-conscious consumers who read labels carefully.

Free of Vitamin K2. Natto naturally contains both nattokinase and Vitamin K2, which coexist without issue in food form. But in a supplement context, K2 accumulation is a consideration for anyone taking higher doses long-term, or for those already supplementing K2 separately. BioAbsorb removes K2 from its nattokinase formulation — allowing flexible dosing without the K2 management concerns that apply to some competing products.

Each capsule delivers 100 mg nattokinase at 2,000 FU activity — consistent with the dose used across the major clinical trials reviewed above. The product is manufactured in a Canadian GMP-certified facility, third-party tested for potency (≥2,000 FU per capsule), heavy metals, gluten, and microbial contaminants. The formulation is 100% vegetarian, Non-GMO, and free of gluten, dairy, nuts, eggs, fish, shellfish, and all animal products. The 180-capsule option provides a six-month supply at $49.87 — approximately $0.28 per day, representing strong cost-per-dose value relative to comparable products. The recommended protocol is one capsule daily on an empty stomach.

Frequently Asked Questions

What is nattokinase used for?

Nattokinase is primarily researched for cardiovascular applications: supporting healthy blood pressure, promoting fibrinolytic activity (the body's ability to break down excess fibrin and blood clots), and contributing to arterial health. It is used as a complementary approach to cardiovascular wellness — not as a replacement for prescription medications — and is most appropriate for health-conscious adults proactively managing cardiovascular risk factors. Clinical research to date focuses almost entirely on cardiovascular outcomes, though emerging research also examines anti-inflammatory and neuroprotective properties.

How long does nattokinase take to work?

A single oral dose of 2,000 FU produces measurable fibrinolytic activity in the bloodstream within approximately 4 hours. However, the clinically meaningful benefits seen in blood pressure trials — reductions of 3 to 5 mmHg — consistently emerge at the 8-week mark of daily supplementation. Nattokinase is not a fast-acting acute supplement; its cardiovascular benefits appear to be cumulative and depend on consistent daily use over weeks.

Can I take nattokinase with blood pressure medication?

Possibly, but this requires physician involvement. Nattokinase has independent antihypertensive effects, and combining it with prescription antihypertensives could produce additive pressure reductions that require monitoring. More critically, if any of your medications are anticoagulants or antiplatelet drugs (including aspirin), nattokinase's fibrinolytic activity may increase bleeding risk in combination. Disclose nattokinase to your cardiologist or prescribing physician before starting — they can assess your specific medication profile and risk factors.

Is nattokinase the same as serrapeptase?

No — they are distinct enzymes with different mechanisms, research bases, and primary applications. Both are systemic enzymes with fibrinolytic properties, but nattokinase has a substantially stronger evidence base for cardiovascular outcomes (blood pressure, fibrinolysis, arterial health), while serrapeptase has been studied more in the context of inflammation and sinus conditions. They work through different molecular pathways and should not be treated as interchangeable. For a head-to-head comparison, see nattokinase vs. serrapeptase.

Does nattokinase have side effects?

At the standard 2,000 FU clinical dose, nattokinase appears to be generally well-tolerated in short-term studies, with mild gastrointestinal effects (nausea, diarrhea, constipation) reported in a minority of participants. The most significant risk is additive bleeding potential when combined with anticoagulant or antiplatelet medications. People with clotting disorders, hemorrhagic stroke history, active ulcers, or those approaching surgery should avoid nattokinase or seek medical guidance before use. See the full side effects guide for a complete overview.

Can I get nattokinase from food instead of supplements?

Nattokinase is found in natto — a fermented soybean food with a strong flavor and sticky texture that is not widely eaten outside Japan. While natto contains meaningful enzyme activity, the dose is variable and difficult to standardize, and the food is not practical for most Western consumers. Supplements offer a standardized dose (100 mg / 2,000 FU) with consistent potency testing, making them more reliable for therapeutic use. For a full comparison of food sources versus supplementation, see nattokinase from food vs. supplements.

Conclusion

Nattokinase is one of the more rigorously studied natural enzymes for cardiovascular health — with human trial data supporting its effects on blood pressure, fibrinolytic activity, and arterial health at clinically relevant doses. The evidence is not definitive enough to position it as a standalone therapeutic, but it is strong enough to make it a credible complementary option for adults managing cardiovascular risk factors, provided drug interactions are assessed by a physician. If you are considering adding nattokinase to your routine, BioAbsorb's Nattokinase Enzyme — 2,000 FU per DRcaps delayed-release capsule, tested for potency and contaminants, free of Vitamin K2 and common allergens — offers a formulation built around the delivery and purity factors that matter most.

Research References

1. Nattokinase Supplementation and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Reviews in Cardiovascular Medicine, Vol. 24 (2023). Meta-analysis of 6 RCTs (546 participants) finding significant reductions in systolic (−3.45 mmHg) and diastolic (−2.32 mmHg) blood pressure with nattokinase supplementation versus placebo.
2. Nattokinase: A Promising Alternative in Prevention and Treatment of Cardiovascular Diseases. Integrative Medicine Insights, Vol. 13 (2018). Comprehensive review documenting nattokinase's fibrinolytic, antihypertensive, anti-atherosclerotic, antiplatelet, and neuroprotective effects and its role in the fibrinolysis cascade including PAI-1 inactivation.
3. A Single-Dose of Oral Nattokinase Potentiates Thrombolysis and Anti-Coagulation Profiles. Scientific Reports, Vol. 5 (2015). Double-blind crossover study in 12 healthy males demonstrating measurable fibrinolytic activity in the bloodstream within 4 hours of a single 2,000 FU dose.
4. Consumption of Nattokinase Is Associated with Reduced Blood Pressure and von Willebrand Factor: Results from a Randomized, Double-Blind, Placebo-Controlled, Multicenter North American Clinical Trial. Integrated Blood Pressure Control, Vol. 9 (2016). 74-subject North American RCT finding significant diastolic BP reduction (87→84 mmHg) and reduced von Willebrand factor after 8 weeks of 100 mg/day nattokinase.
5. Effects of Nattokinase on Blood Pressure: A Randomized, Controlled Trial. Hypertension Research, Vol. 31 (2008). 86-participant double-blind RCT showing systolic blood pressure reduction of 5.55 mmHg after 8 weeks of 2,000 FU/day nattokinase in subjects with pre-hypertension or stage 1 hypertension.
6. Effective Management of Atherosclerosis Progress and Hyperlipidemia with Nattokinase: A Clinical Study with 1,062 Participants. Frontiers in Cardiovascular Medicine, Vol. 9 (2022). Large retrospective clinical study finding 21.7% reduction in carotid intima-media thickness and measurable plaque reduction after 12 months of nattokinase supplementation.
7. Nattokinase. Memorial Sloan Kettering Cancer Center — Integrative Medicine (reviewed 2023). Overview of nattokinase mechanisms, fibrinolytic activity relative to plasmin, drug interaction risks, and clinical evidence summary from a major cancer and integrative medicine institution.
8. Heart Disease Facts and Statistics. Centers for Disease Control and Prevention (2024). Source for cardiovascular mortality statistics: 919,032 deaths from CVD in 2023 (1 in every 3 deaths); one person dies every 34 seconds.
9. Data Recorded in Real Life Support the Safety of Nattokinase in Patients with Vascular Diseases. International Journal of General Medicine, Vol. 14 (2021). Real-world safety study following three groups of patients with vascular conditions taking 100 mg (2,000 FU) nattokinase daily for 30 days, reporting no adverse events.
10. Nattokinase: Dosage, Safety, and Evidence Summary. Examine.com (2024). Evidence-based summary including EFSA safety endorsement for 2,000 FU daily dose, historical use data, and overview of clinical findings on fibrinolytic and blood pressure effects.
11. Research Progress on the Utilisation of Embedding Technology and Suitable Delivery Systems for Improving the Bioavailability of Nattokinase. Journal of Food Bioactives (2021). Review of nattokinase stability under gastric conditions, including inactivation below pH 3, and delivery strategies to improve oral bioavailability.

About the Author

David Kimbell is a health writer, digital entrepreneur and former aerospace engineer, based in Ottawa, Canada. He loves translating complex science into clear, actionable guidance for consumers seeking evidence-based solutions.

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Important Disclaimers

Medical Disclaimer: This article provides educational information only and is not intended as medical advice. Always consult with a qualified healthcare provider before starting any new supplement, especially if you have existing health conditions, take medications, or are pregnant or nursing.

FDA/Health Canada Statement: These statements have not been evaluated by the Food and Drug Administration or Health Canada. This product is not intended to diagnose, treat, cure, or prevent any disease.